PdFe Alloy-Fe5C2 interfaces for efficient CO2 hydrogenation to higher alcohols

Abstract

Direct CO₂ hydrogenation to higher alcohols (HA) is a promising route for high-value utilization of waste CO₂, but developing active and stable catalysts remains a grand challenge. For this reaction, constructing multifunctional interfaces as active sites is required to fulfill controllable C-C coupling of alkyl and CO*/CH_xO* species. Herein, we report a PdFe catalyst with abundant PdFe alloy-Fe₅C₂ interfaces via a PdFe alloy induced FeO_x carbidization process, which can achieve HA yield of 86.5 mg g_cat⁻¹ h⁻¹ with 26.5% selectivity at 300 ºC, 5 MPa, and 6000 mL g_cat⁻¹ h⁻¹. The accelerated deactivation test unveils the PdFe catalyst exhibits better durability than the widely studied CuFe based catalysts against harsh conditions. Multiple in-situ characterization results unveil a synergetic mechanism for HA synthesis at the PdFe alloy-Fe₅C₂ interfaces, where PdFe alloy is responsible for CO formation and non-dissociative activation, while Fe₅C₂ phase promotes CO dissociation and chain propagation.